You look down at yourself. Sure enough, 2 small lumps are pushing off your chest. Calling them boobs would still be a bit presumptuous, but you were not big enough to have man boobs either. Suddenly you felt your donut asshole begin to swell a bit, becoming very prominent as it pushed aside your ass cheeks, a lot more sensitive, and a bit moist too somehow. It felt almost like you were sweating down there. However the pain was rapidly decreasing as this new almost gel-like liquid began lubricating everything.
"Well, that makes this a whole lot more fun." Says your GF as he begins to thrust upwards with such a speed that you feel yourself fly into the air, only for the ring in your ass to stop you. Then you glide down his shaft once again until your ass cheeks bounces off of him. Then he repeats. Due to the gel, you are able to now glide along his shaft very fast, yet you still feel every single bump and ridge of his massive cock. It still feels like it is 3 times too large for your ass, yet you are still moving along it with ease.
Your GF changes his hand position from holding up your arms above your head, to holding you up as he cups your two new lumps of chest fat. His hands are so much bigger than those lumps, and his palm alone covers them entirely, yet it still feels incredible to you. Your nipples have never even been close to this kind of sensitivity before. He isn't even doing anything but covering them with his palms and you are going insain from the pleasure that it alone is bringing you.
Now that he was able to cop a feel, your GF, is able to get a better idea about the situation involving your chest. "Well, they are certainly tiny, but yeah, they seem like breasts. That or you now suddenly have the some of the hardest, most sensitive man nips out there. I'm not an expert though. If they do end up getting bigger, it will be easier to tell if they truely are tits or not."
You look behind your back at your GF and are kind of surprised to see her towering over you a bit. She is easily at least a full head taller now. And that isn't including the difference in terms of leg height, as you are now a few inches off the ground, even if you point down your toes. But you do not feel THAT small either. "You may have gotten taller" you say.
"Well that's obvious. I am definitely taller now. How are you only just realizing this now?" He laughs at you. "Hey look, no hands" he says, letting go of you. You slide backwards down his shaft until your ass is pressed against his crotch and just hang there. Your feet cant touch the ground, nor can you push or pull yourself off of his erect cock, even if your mysterious hard ring wasn't there.
You begin to struggle, unable to do anything about your current situation anymore. Your GF thrusts her pelvis foreward, causing you to slide down his shaft until your donut ring stops you from sliding off his cock. Then you fall as gravity pulls you back down onto his shaft. You feel his cock head press up against something and a chill runs through your entire body as you cum instantly. Your own tiny cock didn't even have time to become hard, as you watch your flaccid penis just start to drool out your jizz in just a few thick globs.
You feel your body then shed a bit of body mass, as your arms and waist thin down to being a very androgynous, if not slightly feminine size. This does not go unnoticed by your GF either. "Damn, its like I am fucking the manliness out of you."
You shake your head at that. "I am still a guy!"
"Well, not if I can help it. Now I wanna see how cute you can get before you actually turn into a girl, if that is the end result at least. Who knows, you may just end up staying as a guy, but one who undeniably both looks and sounds exactly like a girl. Like, just a hyper-feminized boy or something." Your GF says with a huge grin on his face.